Head Gasket

Most of us will never have to deal with a head gasket replacement. But for those unlucky drivers and car owners that have a severe overheating problem, a new head gasket is the only fix for your vehicle. A good set of tools, a high-replacement head gasket and a little knowledge on installation is all that is needed.

But what is a head gasket? The head gasket is one of the most important parts in an engine because it has to seal all of the combustion chambers as well as the coolant and oil channels between the head and block. It has to provide a leak-free seal from the moment it was installed and uphold that seal for the life of the engine – which might well be 150, 00 miles or more on a lot of today’s automobiles.

One reason which makes many engines hard to seal these days is aluminum cylinder heads on cast iron blocks. Aluminum heads has less weight but when they get hot, they expand 1.7 times faster than cast iron. That makes it tougher for the head gasket to uphold a seal with all that thermal cycling with iron heads. In other words, aluminum heads cannot withstand overheating as iron heads could in the past. Another is that, if the head gasket can’t bear up this motion and if it’s not strong enough to withstand the shearing forces that occur every time the engine is started, run and allowed to cool back down, it will leak eventually.

One way gasket manufacturers deal with the scrubbing problem particularly in bimetal engine is to add a non stick coating to the gasket. Teflon, molybdenum and other low friction coatings were used to prevent gaskets from sticking to either surface, allowing the head to expand and contract without tearing the gasket apart. But this technique is very different to what is done in many head gaskets for cast iron engines. Raised silicone, Viton or fluoroelastomer sealing beads are applied to the face of the gasket to increase the clamping pressure. This then improves the gasket’s ability to form a good cold seal and helps it maintain that seal by holding the gasket firmly in place.

Head gasket resilience can also be improved by simply using stronger or reinforced combustion armor, tougher and high temperature fibers like aramid and Kevlar in composition gaskets. Adding extra reinforcements to vital oil hole gromments is also an option.